function s1_generate_a_series_of_files(){
for i in{1..100};do
    echo $i >/tmp/new_file$i
done
}

function s2_list_4_files_in_long_format_about-account_and_group(){ls -1 /etc{passwd,shadow,group,gshadow} | sort -d
}
function s3_find_items_related_to_given_username(){
grep -h $1 /etc/{passwd,shadow} | sort -d
}
function s4_find_items_related_to_given_group_name(){
grep -h $1 / etc/{group,gshadow} | sort -d
}
function s5_create_groups-for_given_group_names(){
groupadd rnd
groupadd itoperation
}

function s6_create_user_and_set_their_group_as_required(){
useradd -G rnd adam
useradd -G rnd bob
useradd -G itoperation calvin
useradd -G itoperation david
useradd -G rnd edward
}
function s7_change_users_shell(){
usermod -s /usr/bin/sh/ adam
usermod -s /usr/bin/sh/ edward
}
function s8_set_password_change_policy(){
passwd -n 10 -x 60 -w 10 adam
passwd -n 10 -x 60 -w 10 bob
passwd -n 10 -x 60 -w 10 calvin
passwd -n 10 -x 60 -w 10 david 
passwd -n 10 -x 60 -w 10 edward
}
function s9_set_password_for_five_users(){
echo "adam:$1" | chpasswd
echo "bob:$2"  | chpasswd
echo "calvin:$3" |chpasswd
echo "david:$4" |chpasswd
echo "edward:$5" |chpasswd
}
function s10_lock_bobs_password(){
usermod-L bob
}
function s11_include_adam_into_wheel_group(){
usermod -a -G wheel adam
}
function s12_change_files_permission(){
for i in{1..33};do
chmod -R 640 /tmp/new_file$((3*i))
done
}
